Label the parts (a), (b), (c) and (d) and show the direction of flow of electrical signals in Figure 7.2.
(a) Sensory neuron
(b) Spinal cord (CNS)
(c) Motor neuron
(d) Effector (muscle in arm)
Name the plant hormones responsible for the following:
(a) elongation of cells
(b) growth of stem
(c) promotion of cell division
(d) falling of senescent leaves
(a) Auxin
(b) Gibberellin
(c) Cytokinin
(d) Abscisic acid
Label the endocrine glands in Figure 7.3.
(a) Pineal gland
(b) Pituitary gland
(c) Thyroid
(d) Thymus
In Figure 7.4 (a), (b) and (c), which appears more accurate and why?
Figure (a) is more accurate because plant shoots are negatively geotropic and grow upwards, while roots are positively geotropic and grow downwards.
Label the parts of a neuron in Figure 7.5.
(a) Dendrite
(b) Cell body
(c) Axon
(d) Nerve ending
Match the terms of Column (A) with those of Column (B).
(a) → (iii)
(b) → (iv)
(c) → (i)
(d) → (ii)
What is a tropic movement? Explain with an example.
Tropic movements are directional growth movements of plants toward or away from a stimulus. For example, in phototropism, shoots bend toward light while roots bend away from light.
What will happen if intake of iodine in our diet is low?
(a) Release of thyroxin from the thyroid gland will be reduced, affecting protein, carbohydrate and fat metabolism.
(b) A person may suffer from goitre due to iodine deficiency.
What happens at the synapse between two neurons?
When an electrical signal reaches the axonal end of one neuron, it releases chemical substances that cross the synapse and generate a new electrical signal in the dendrite of the next neuron.
Answer the following:
(a) Which hormone is responsible for the changes noticed in females at puberty?
(b) Dwarfism results due to deficiency of which hormone?
(c) Blood sugar level rises due to deficiency of which hormone?
(d) Iodine is necessary for the synthesis of which hormone?
(a) Oestrogen
(b) Growth hormone
(c) Insulin
(d) Thyroxin
Answer the following:
(a) Name the endocrine gland associated with the brain.
(b) Which gland secretes digestive enzymes as well as hormones?
(c) Name the endocrine gland associated with kidneys.
(d) Which endocrine gland is present in males but not in females?
(a) Pituitary gland
(b) Pancreas
(c) Adrenal
(d) Testes